Questions tagged [weather]
Weather means the atmospheric conditions, including wind, temperature and precipitation, in a specific area at a specific time.
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How can I determine the level of clouds of operational significance in METAR?
Considering that
Minimum sector altitude of the airport = 10500 feet
Airport elevation from MSL = 2500 feet
What is the level of clouds of operational significance in METAR for this airport? Should we ...
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How Low pressure moves across land [migrated]
I understand that low pressure systems ( like hurricane ) , can move across ocean since they are constantly fed by warm air from below .
But what is it that enables it to move across land ? Especially ...
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What weather conditions have been tested with a wind tunnel?
If I want to know how my aircraft component performs in different atmospheric conditions, I might want to test it in a wind tunnel. What sorts of weather conditions have been tested in a tunnel?
I am ...
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How can I get prior days weather information?
If I want to get airmet information for prior days, like say last week or last month, how can I do that? Specific instructions would be appreciated.
(So, this would be information like winds aloft and ...
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Is ISA deviation always zero at the stratosphere?
I watched a video of a pilot who stated that the ISA deviation is always near zero when at the stratosphere, is this true? And if so, what is the science behind it?
Here is the video
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What relationships exist between pressure systems and fronts?
I'm a student studying weather systems and believe I understand that high pressure systems are areas of colder descending air that tend to dissipate cloudiness and provide good weather and clear skies....
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What’s the math on finding your Freezing level?
If the std temp lapse rate is 2c per 1000, and the freezing level is 0c.
If at the sfc my temp is 4c wouldn’t the freezing level be at 2,000?
If so I calculated this using a long method. Is there a ...
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How to find altimeter settings for higher altitudes?
I am trying to calculate cruise performance, but how would I find the altimeter setting for a given altitude?
I’ve looked at charts but they only show altimeter settings for the surface.
Would I use ...
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How does temperature affect the altimeter [duplicate]
Hi Im having a time understanding Pressure levels as it relates to the altimeter.
The answer says. The limitation of the altimeter is that, On warm days pressure levels are raised higher than on a std ...
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What would define a thunderstorm that you would stay 20 miles away from?
In summer time, we get pop up cumulonimbus clouds that often develop into thunderstorms. So is there a defined point at which it would be considered a thunderstorm to stay 20 miles away from? Is it ...
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is pressure altitude at different temperatures (different days) on the ground at the same airfield the same?
let's say we are at x-airfield which is at 0 MSL on the ground. We set the Kollsman window to 29.92 on a standard day, whatever the read is that would be the Pressure altitude, correct? (ideally zero ...
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Can I takeoff as VFR from class G with 2sm vis. even if that's IFR in the categorical outlooks?
Weather minimums for class G during the day (below 1200'AGL) are 1SM vis. and clear of clouds.
The categorical outlook (AIM 7-1-7) for IFR is 1sm to 3sm visibility and a ceiling of 500'AGL to 1000'AGL....
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How do IFR flights in IMC in Class G airspace not collide?
According to Wikipedia, in Class G airspace, "Operations may be conducted under IFR or VFR. ATC has no authority but VFR minimums are to be known by pilots. Traffic Information may be given as ...
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Will FIS-B replace onboard Doppler radars?
Will FIS-B technology replace onboard Doppler radars?
These radars can cost upwards from $20,000. Would FIS-B update quick enough to make this a efficient swap?
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Does high speed airflow remove water from the plane's windshield more effectively?
I have read something from the web that mentions higher speed reduces visibility during rain because water spreads over a larger area and the plane impacts droplets more frequently.
I think that ...
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Jet Stream effects at 60.000 ft
Today's airplanes cruise at 40,000 feet. Easterly flight times are longer than their westerly components due to the direction of the jet stream. Comercial supersonic flights did/will cruise at 60,000 ...
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How is “mountain obscuration” determined?
Living in southeast Washington, ForeFlight often paints large swaths of mountainous terrain to the east as IFR “mountain obscuration”. I live at the foot hills, and often as I look that way, I see ...
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How impactful is De-icing on flight margins?
A quick google search suggests that deicing is a very expensive activity, with many suggesting it might be 5-10k for both deicing and anti-icing fluid.
Given that flight costs typically are lower for ...
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Honeywell 880 weather radar malfunctioning
Is anyone aware of issues with the Honeywell 880 weather radar not painting moisture? We had our original 800 unit go bad on our Falcon 7X, We have installed 3 replacements that have hardware and ...
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PTCHY LGT MOD SEV coverage on WX charts?
On GFAs, TAFs, METARs we see PTCHY LGT TURB, MOD TURB, -RA, +RA, etc. I was wondering where could I find the technical definition of these terms? For example the percentage coverage of these weather ...
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Why did this flight, that usually flies around 40,000ft only fly at around 29,000ft for the route?
Looking at the flight BY6272 BRS-PMI, it was considerably delayed and flew (according to the flight radar app) at 29,000 feet rather than its usual 40,000 for this same route. It is a Boeing 787 ...
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Does a plane's service ceiling vary with season/temperature?
Aircraft use barometric altitude, e.g. FL300 is the barometric altitude of 30,000 ft MSL. In winter however, FL300 is actually lower than the absolute altitude of 30,000 ft because of a cold and ...
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How to determine the base of stratus clouds? [closed]
For cumulus clouds this applies
Calculate the 'spread,' where you're taking the current surface temperature and subtracting the dew point.
Divide the spread by 4.4 (if temperatures are in °F) or 2.5 (...
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What are dry and saturated lapse rates values or ranges for a rising or lowering parcel of air in degrees Celsius?
Environmental lapse rate average is rounded to 2 degrees celsius per 1000 ft.(Note that environmental lapse rate varies through the day).What about parcel of air lapse rate.? Dry lapse rate is a ...
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Which countries use qfe field pressure?
I heard that acrobatic flight, Russians, Americans use qfe but is it always the case?
Also why doesn't everyone use it?
Isn't qfe field pressure better than qnh local pressure...
Does a pilot ever use ...
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If while landing ,a surface inversion occured close to the ground would atc or atis know?
A change in temperature, pressure and many factors might happen in a surface inversion.Thus affecting landing performance and calculation.The local peessure might change suddenly as well...
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Who gives us transition level when it varies?
Who gives us transition level when it varies?
ATC, ATIS, any others?
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Why is rare to see landings from East to West at the AJU airport?
Every day at the Aracaju - SE, Brazil Airport (IATA: AJU, ICAO: SBAR) planes take off from West to East and lands from East to West. But in rare occasions they will land from West to East. I think it ...
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Why would a pilot need to change their heading when flying through a cold front?
When doing my PPL written review there is a question, simply can't get my head wrapped around the reason why and have searched everywhere. It's definitely a very simple thing, however, I am missing ...
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When must ATC give wind variation and gust?
In connection with takeoff and landing, ATC will give the current wind direction and velocity to the pilot. In some cases, ATC will also report the variation in direction and/or current gust (max and ...
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Difference between "pressure levels raising on warm days causing lower IA" and "TA being higher than IA on warm days" [duplicate]
IA: Indicated altitude
TA: True altitude
I have seen this picture before:
Concept 1
and I understand this. On cold days, the pressure gradient is shorter which means the indicated altitude at a ...
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Is temperature inversion good or bad?
When there is temperature inversion, I heard that convection is suppressed and hence the layer of air is stable.
But I also see the following questions when studying for my PAR:
A pilot can expect a ...
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Is the pressure change due to volcanic activity a concern?
The recent eruption of the Hunga Tonga–Hunga Ha'apai sent a shockwave so massive that it got picked all over the world by weather stations.
This is the pressure detected one in Italy (source), where ...
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Formation of Clouds in High Pressure Systems (Western Australia - Perth) [closed]
High pressure systems are normally correlated with stable atmospheric conditions with little to no cloud cover, but due to this minimal cloud cover, doesn't that open up the ocean / ground moisture to ...
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How far does the lightning detector work at an AWOS station, as reported in a METAR?
I noticed on my local airport's METAR that there was distant lightning to the east. I am near Kansas City. When I looked at radar, the only possible system that could produce lightning was in the St. ...
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What is considered to be a flight into known Icing?
I am aware that flight into known icing is prohibited if your aircraft is not suitable to fly in icing conditions (unless e.g.: FIKI,...). Given the following example I am wondering if it would be ...
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What is Tendency of RVR?
What does tendency of RVR (Runway Visual Range) mean and why down and up have the same values?
This is from AWOS(Automated Weather Observing System)
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What does AO2A in the remarks of a METAR mean?
I am familiar with AO2 in the METAR remarks as described in this answer, which means the station is automated and has a precipitation discriminator. I have noticed sometimes there is AO2A in the ...
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Will a jet flown on a parabolic arc reach its highest altitude on a warm day or a cold one?
In level flight, on cold days jet-powered planes can fly higher because the air is denser. However, at the same time the true airspeed is lower because of the denser air.
At warmer temperatures a ...
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Why would "hot gases" from a volcano damage helicopter rotors?
In the ongoing story about someone trying to rescue dogs from a volcano with a drone, I keep seeing variations of this claim repeated:
Spanish authorities have dropped food down to the dogs with ...
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Station pressure vs. reported altimeter
I must be missing something big. Page 12-5 of the PHAK tells me that a station at 5,000 feet above sea level would convert its 24.92 pressure reading to 29.92. I understand that this helps to track ...
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Why are pressure levels raised on warm days?
As I'm studying for the PPL knowledge exam, I had the following note:
Pressure levels are raised on warm days and the indicated altitude is lower than true altitude.
(source: AOPA)
But I don't quite ...
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What is inflated wind speed?
According to NOAA, inflated wind speed is "the true wind speed (in knots) adjusted to improve forecasts of higher wind speeds. Wind speeds greater than the mean wind speed observed are increased, ...
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Best way to forecast density altitude?
Let's say I'm planning a day trip from a low elevation home base to a warm, mountainous location. I wake up early, check the weather, do performance calculations based on current METARs, and decide to ...
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Why is the minimum for VFR 1000/3 while there are VFR weather minimums for every single airspace?
It seems like I have a concept error here. I don't understand why "the VFR min is 1000/3" when I think I would need to check in which airspace I am to then check for its respective weather ...
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Effect of heat and humidity on take off, descent, climb, and cruise
I am aware of this question, this resource (phak), and this resource that explains the science, but I am looking for a more straightforward answer.
I am student pilot and there's a lot of literature ...
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What kind of weather conditions would produce turbulence with an intensity of 90 feet per second?
This is the official documentation that we found regarding current commercial airplane design criteria; https://www.law.cornell.edu/cfr/text/14/25.341
It says the criteria for continuous turbulence is ...
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Why does the Winds Aloft ‘For Use Time’ start before the ‘Valid Time’?
Why is it that a winds aloft forecast normally has a "valid time" that comes in the middle of the "for use" time range? Why don't they just state the valid time as the beginning of ...
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What does Region @TOP mean on the aviationweather.gov website?
When looking at raw METAR data on the aviation weather center, "@TOP" appears in the text box where you can type identifiers. What does TOP mean?
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Do airliners get substantially different weather briefings from the rest of us?
Southwest Airlines flights were delayed and cancelled this week due to an outage in their third-party weather provider. I understand if they have a streamlined business process for getting weather ...
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